Safety-lock for lifting-jacks



1,368,793. 1 fmnwf1l Feb. 15, 1921 F. L. GORMLEY.

SAFETY LOCK FOR LIFTING JACKS. APPLicATloN FILED Nov. 19, |919.

In@ enh) r l'rqIJi Gormcy SNT 51.

FRANK L. GORMLY, 0F BROOKLINE,MASSACHUSETTS, ASSIGNOR T0 A.. O. NORTON,YZENO., 0F BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE.

SAFETY-LOCK FOR LFTING-JACKS.

Specification of Letters Patent.

Patented Feb. 1921.

. Improvements in Safety-Locks for Lifting- Jacks, of which thefollowing is a specification.

This invention relates to'safety locks for lifting jacks which areprovided with'means Vwhereby the jack may be automatically lowered bythe weight of the load.

In jacks of this character, it often happens that under excessive loadsthe brake members coacting with the brake wheel, will be insufficient toretard the rotation of the brake shaft yespecially when considerablemomentum has been imparted to said brake wheel.

As a consequence, it is desirable to provide a positive lock which willeffectually prevent the rotation of the brake shaft in case the brakemembers should fail to operate for any reason.

The present invention consists in provid-v ing the brake wheel with oneor more sockets in the face thereof with which, under abnormalconditions, a spring-pressed pin is adapted to engage before the brakewheel has made a complete revolution thereby locking it from furtherrotation! The invention further consists in certain For the purpose ofillustrating the inven-` tion, one preferred form thereof is illustratedin the drawings, this form having been.

found to give satisfactory and reliable re* sults although it is to beunderstood that the various instrumentalities of which the inventionconsists can be variously arranged and organized and the inventionis notlimited to the precis/e arrangement and organization of theseinstrumentalities as herein shown and described, except as required bythe scope of the appended claims.

Of the drawings:

Figure 1 represents an elevation of a portion of the frame of a liftingack and showing the arm for controlling the braking device.

F ig. 2 represents a vertical section of the same on line 2, 2, F ig. 3showing the brake wheel in elevation and other parts in part section.

Fig. 3 represents a section on line 3, 3, on Fig. 1 and showing theoperating arm patly in elevation and partly in section, an

Fig. l represents a modified form of brake wheel.

Similar characters indicate like parts throughout the several figures ofthe drawings.

CII

In the drawings, 10 is a portion of the framework of a lifting jack suchas is disclosed in the application above referred to on which thepresent invention is an improvement.

A cover plate 11 is secured to this frame work 10 by means of screws orother similar members 12. i

To the rear face of thc cover plate 11 is secured a bracket 13 in whichis revolubly mounted a shaft 1li having a brake'wheel 15secured'thereto. This brake wheel 15-has elongated sockets or openings16 extending therethrough, said sockets or openings 16 beingdiametrically disposed therein.

The bracket 13 has also pivoted thereto at 17, 17, the curved brakemembers 18, 18, which are adapted to contact with the periphery of thebrake wheel 15 and retard the rotation thereof to prevent the jackloWering too rapidly under an excessive load.

The lower Vface of the Vbrake members 18 have sockets 19 formed thereinin which are positioned the inner ends of springs 20, the outer ends ofwhich are positioned respectively in sockets 21 in the cover plate 11and 22 in the bracket 13.

These springs 2O normally retain the brake members 18 in frictionalcontact with the periphery of the brake Wheel 15.

A-headed screw or bolt 23 is also mounted l v in the cover plate 11 asindicated in Fig. 3

of the drawings, and mounted upon the unthreaded portion of the screw orbolt 23 is a cylindrical hub 24 ,having oppositely disposed attenedsides 25 on the inner end thereof.V` Y l These flattened sides 25 arenormally parallel with the inner faces of the lower ends of the brakemembers 18.

The `hub 24 has an arm 26 extending radially therefrom, the outer end ofwhich is provided with a hub V2,7' having formed therein a socket 28 inwhich is mounteda cylindrical pin 29, the diameter of which is less thanthe width of the sockets or openings 16 in the brake wheel 15.

A milled head 30 is secured to theiouter"V end of 'the reduced shank ofthel pin 29 by means of the member 31. Y

ldithin the socket 28 and surroundingt'he reduced shank of the pin 29 isa spring V32 which normally forces the pin 29 outwardly.

, thesesprings 20 forcing thelower ends of Y The inner end of the hub 27extends through a curved slot 33 formed in the side walls of theframework and the cover Y plate 11.

The arm 26 is provided with a lateral extension 34 which covers `theslot 33 when said arm 26 is in its normal position as indicated inVVFig.v 1 of the drawings. This plate prevents dirt from passing through vtheslot 33 when thejack is not in use. Y The, spring 32 is considerablylighter than the springs and as a consequence,

the brake members 18 intocontact with the flattened faces of the hub24,' normally retain the hub 27 of the arm 26 at the right hand end ofthe slot 33 with its axis in alinef v `ment with the sockets 16.A Y

This permits the locking Ypin .29 to be' path of movement of Vthe forced'into one of the sockets voropenings 16 by means of the spring 32 thusefectually'preventing the operationV of the jack.

`When 'it is desired to lower the load, the operator seizes the milledhead and withdraws the Vlocking pin 29 from the socketf16 and moves thearm 26 about its axis until the locking pin 29 is at the opposite end ofthe slot 33 and lout of register. with .the path kof movement ofthesockets 16 as the bralze wheel 15 revolves. f

This movement of the arm 26 removes the brake members V18 from contact-with the wheel 15 and permits the jack to lower.

, During the lowering of theV jack, it is essential that the operatorretain his hold upon the head 30 and keep the lockingpin 29 within thesooket28 and out of register 1 with the path of movement of the socketsor openings 16.

Should the operator remove his hand, for any reason, from the head '30,the spring 32 Y duringthe lowering operation.

would immediately force the inner end of the pin 29 into Contact withtherouter face of the brake wheel 15 and the springs 2O acting uponthe'flat faces 25 of thehub 2e' will immediately return the arm 26 toitsnormal position as indicated in Fig. 1 of theV drawings, with the'axisof the pin 29 in the path of movement ofthe ,sockets 16.

As a result, as soon as either of the sockets V1'6 reachesthe pointopposite tothe-.pin 29, .the spring 32 Vwill foicethe pin29 into 'said'socket 16, thuSV POSitiivGY and @um inat-ically locking the brake wheel15 from further rotation as soon las the en d wall of the socket 16contacts with said pin. Y

vInstead of forming two sockets 16 in theV brake'wheel 15, as shown inFig. 2, a modified form of brake wheel may rbeused with an annularcontinuous groove 16Y` in one ijace in which are positioned twodiametrically disposed stop pins which are adapted to engage with thelocking pin 29 to prevent rotation of the brake wheel 15.

This construction makes the self-lowering jack positively fool-proofV7for as soon as the operatorceases to retain his grasp upon the head 30,the various instrumentalitiesV ofthe device willV automatically operateforcing thelocking' pinrinto the rstV socket prevented Y `lt "isYbelieved that vthe operation and l manyV advantages of the inventionwill be readily understood without further description. i

HawingV thusY described my invention, I

claim: Y l

1. `In a'device 'of theiclass described, a re'v'ol'uble brake wheel abrake me'mber normally coacting therewith; a'oam for removfor actuatingsadcam; and means carried iio iisV ing said member fromsaid wheel;Ya'narm f by said Varm adapted to ooa'ct with saidY wheel andVpositively lock :the wheel from rotation.

v2. Ina device ofthe class described, a V Y revollibl'e brake wheelhaving a socket in f one face; a brakemember normally coact-` ing'the'rev'vith';` a Vcam for removing said member from said wheel; an arm`for'actuating said cam;A and afspring-pres'sed pin carried by said armadapted tocoact with the'socket in said wheel and positively 4lock thewheel from rotationA 3. In adevi'ce Vof lthe classydescribedfa isoVrevoluble brake Wheel for a lifting jack having a socket in one face; aspring-pressed brake member adapted to coact with the periphery of saidWheel; an oscillating cam adapted to remove said member from said Wheel;an arm for actuating said cam provided With a hub extending through aslot in the frame of said jack; and a springpressed pin in said hubadapted to coact with said socket to prevent the rotation of said brakeWheel.

4. In a device of the class described, a revoluble brake Wheel for alifting jack having a socket in one ace;.a brake member adapted to coactwith the periphery of said Wheel; an oscillating cam adapted to removesaid member from said Wheel; an arm for actuating said cam provided witha hub extending through a slot in the frame of said jack; aspring-pressed pin in said hub adapted to coact with said socket toprevent therotation of said brake Wheel; and resilient means coactingwith said brake member and normally retaining said hub at one end ofYsaid slot With its axis registering with the path o movement of saidsocket and forcing said brake member into contact With said wheel. A

5. In a device of the class described, a revoluble brake Wheel for alifting jack hav ing a socket in one face; a pivoted brake memberadapted to coact With the periphery7 of said Wheel; an oscillating armhaving at its pivot a cam adapted to remove said member from said Wheeland having a hub at its outer end extending through a Curved slot in theframework of the jack; a springpressed locking pin in said hub adaptedto enter said socket When the aXis of said socket and pin are inregister; and means coacting With said brake member for normallyretaining said hub at one end of said slot in the framework of the jack;a springl pressed locking pin in said hub adapted to enter said socketwhen the axis of said socket and pin are in register; means for normallyretaining said hub at one end of said slot; and a lateral extension tosaid arm adapted to cover said slot when said arm is in normal position.

7. In a device of the class described, a revoluble brake Wheel having astop shoulder in one face; a brake member normally coacting With saidbrake Wheel; a cam for removing said member from said Wheel; an arm foractuating said cam; and a pin carried by said arm adapted to be movedinto the path of said stop shoulder.

8. In a device of the class described, a revoluble brake Wheel having astop shoulder in one face; a brake member normally coacting With saidbrake Wheel; a cam for removing said member from said Wheel; an arm foractuating said cam; and a springpressed pin carried by said arm adaptedto be moved into the path of said stop shoulder.

Signed by me at 746-7 Old South Bldg., Boston7 Mass., this 17th day ofNovember, 1919.

FRANK LQ eoRMLEY.

`Witnesses WALTER E. LOMBARD, NATHAN C. LOMBARD.

